Design of new type biomass pellet forming machine with plunger roller and ring-die at room temperature

Xiangyue Yuan, Zhongjia Chen

School of Technology, Beijing Forestry University, Beijing, 100083 China

Bio-energy has become the fourth major energy resource after oil, coal, natural gas energy on account of the properties of green, clean, and renewable. And biomass densification is an important technology which makes the biomass resource be low cost and high value. But for current biomass forming equipment, there exist common shortcomings of high energy consumption, low efficiency, serious wear of forming parts, and etc. In this paper, a forming mechanism of a new type biomass pellet machine with plunger roller and ring-die was proposed, which using the mesh extrusion pressure between plungers and forming cavities (or called holes) to make the loose biomass material densification. It could avoid direct contact and intense friction of forming parts and biomass materials out of the holes. So the energy consumption of the materials in ineffective forming process was reduced and the wear of forming parts was effective alleviated. Then the new type biomass pellet forming machine was designed according to the requirements by Solidworks after force analysis and theoretical calculation, and a prototype was built with the whole power 22 kW and production capacity 450 kg/h. Compression experiments were done finally on the prototype. It was shown that the forming quality of solid pellet fuel tended to be stable after 30 minutes’ running and the pellet density could reach more than 0.8 g/cm3. So it represented that the designed pellet machine had a good practical operation and met the design demands.